Materials Literature
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Abstract This article reviews recent topics in the controlled synthesis of polycarbonates and polylactones with small polydispersity indices by activated monomer cationic ring‐opening polymerizations, especially with new initiator systems, such as alcohol/protonic acid and boron alkoxide/protonic acid. © 2002 Wiley Pe…
First-principles calculations based on spin-polarized density functional theory (DFT) and the generalized gradient approximation (GGA) have been used to study the adsorption of CO and NO molecules on the rutile (TiO 2 ) (110) surface in the presence of oxygen vacancy sites. The calculations employ slab geometry and pe…
A high-pressure Raman study of microcrystalline tungsten oxide was performed in the 0.1 MPa-30 GPa pressure range under hydrostatic and non-hydrostatic conditions. Two phase transitions are evidenced; they take place below 0.1 GPa and at about 22 GPa and are of first order. Two spectral anomalies are observed at about…
We report a detailed study of the optical reflectance in sputter-deposited, nanocrystalline silver thin films in order to understand the marked changes in color that occur with decreasing particle size. In particular, samples with an average particle size in the 20 to 35 nm range are golden yellow, while those with a…
Abstract The melt‐state viscoelastic properties of nanocomposites prepared with a symmetrical polystyrene–polyisoprene block copolymer and organically modified layered silicates are examined. Nanocomposites based on three thermodynamically equivalent organically modified layered silicates, primarily differing in later…
The morphology of ultrathin epitaxial MgO layers reactively grown on Ag(001) was investigated by using scanning tunnelling microscopy. In the initial deposition stage Ag atoms are partially removed from the substrate and form extended monoatomic islands leaving vacancy islands in the substrate itself. On individual su…
CRYSTMET is a database of critically evaluated crystallographic data for metals (including alloys, intermetallics and minerals) and associated bibliographic, chemical and physical information. Also included are simulated powder diffraction patterns for all of the entries. The database currently contains almost 70,000…
We show that the resistivities perpendicular ${\ensuremath{\rho}}_{c}$ and parallel ${\ensuremath{\rho}}_{a}$ to the basal planes of different graphite samples show similar magnetic-field-driven metal-insulator transitions at a field ${B}_{c}$\ensuremath{\sim}0.1 T applied parallel to the c axis. Our results demonstra…
The International Centre for Diffraction Data (ICDD) is responding to the changing needs in powder diffraction and materials analysis by developing the Powder Diffraction File (PDF) in a very flexible relational database (RDB) format. The PDF now contains 136,895 powder diffraction patterns. In this paper, an attempt…
Abstract We have successfully incorporated Diels–Alder reversible chemistry into epoxy resins. The Diels–Alder chemistry goes in the forward direction at 60 °C and reverses at or above 90 °C. One resin was formulated with other commercial ingredients into foamed epoxy. The foam, shown to have mechanical properties sim…
The breathinglike phonon modes of multiwalled carbon nanotubes are studied within a valence force field model for nanotubes with two and three layers of armchair type and within a continuum model for nanotubes with a large number of layers. A bond-polarizability model is used to calculate the nonresonant Raman intensi…
Abstract Maleated polyethylene (PEMA)/silicate nanocomposites with a different aspect ratio of silicate and maleated PEMA/SiO 2 composite were prepared by melt intercalation. The nanocomposites with a high aspect ratio silicate (montmorillonite) showed a faster decrease in the terminal slope of the storage modulus and…
The Nucleic Acid Database was established in 1991 as a resource to assemble and distribute structural information about nucleic acids. Over the years, the NDB has developed generalized software for processing, archiving, querying and distributing structural data for nucleic acid-containing structures. The architecture…
The International Centre for Diffraction Data (ICDD) produces the Powder Diffraction File (PDF). This paper discusses some of the seminal events in the history of producing this primary reference for powder diffraction. Recent key events that center on collaborative initiatives have led to an enormous jump in entry po…
We study the steady state properties of a 2D granular mixture in the presence of energy driving by employing simple analytical estimates and Direct Simulation Monte Carlo. We adopt two different driving mechanisms: a) a homogeneous heat bath with friction and b) a vibrating boundary (thermal or harmonic) in the presen…
A detailed Linear Combination of Atomic Orbitals (LCAO) tight-binding model is developed for the layered High-Temperature Superconductor cuprates. The band structure of these materials is described using a sigma-band Hamiltonian employing Cu4s, Cu3d_x^2-y^2, O2p_x and O2p_y atomic orbitals. The Fermi level and the sha…
We describe a method for computing the response of an insulator to a static, homogeneous electric field. It consists of iteratively minimizing an electric enthalpy functional expressed in terms of occupied Bloch-like states on a uniform grid of k points. The functional has equivalent local minima below a critical fiel…
We analyze particle velocity fluctuations in a simulated granular system subjected to homogeneous quasistatic shearing. We show that these fluctuations share the following scaling characteristics of fluid turbulence in spite of their different physical origins: 1) Scale-dependent probability distribution with non-Guas…
We study numerically the minimum energy path and energy barriers for dislocation nucleation in a two-dimensional atomistic model of strained epitaxial layers on a substrate with lattice misfit. Stress relaxation processes from coherent to incoherent states for different transition paths are determined using saddle poi…
Static and dynamic changes induced by adsorption of atomic hydrogen on the NiAl(110) lattice at 130 K have been examined as a function of adsorbate coverage. Adsorbed hydrogen exists in three distinct phases. At low coverages the hydrogen is itinerant because of quantum tunneling between sites and exhibits no observab…